1. Field of the Invention
The present invention relates to a novel dielectric ceramic composition and a novel dielectric material that exhibit high dielectric constants and high Q-values in high-frequency regions such as of microwaves, milliwaves and like waves.
2. Description of the Prior Art
The dielectric ceramics are widely used as dielectric resonators and as dielectric substrates for MICs in high-frequency regions such as of microwaves and milliwaves.
As the dielectric ceramics of this kind, there have heretofore been known, for example, ZrO.sub.2 -SnO.sub.2 -TiO.sub.2 type materials, BaO-TiO.sub.2 type materials, (Ba, Sr)(Zr, Ti)O.sub.3 type materials, and Ba(Zn, Ta)O.sub.3 type materials.
Owing to improvements in regards aspects, the above-mentioned materials now have properties such as dielectric constants of 20 to 40 and Q-values of 1000 upto 3000 at frequencies of 500 MHz upto 5 GHz, as well as a temperature coefficient (.tau.f) of resonance frequency of around 0 ppm/.degree. C.
In recent years, however, more improved dielectric properties and, particularly, further increased Q-values have been demanded for the dielectric materials accompanying the trend toward using ever higher frequencies. With the above-mentioned conventional dielectric materials, at the present condition high Q-values of practical level are not imparted that can be applied in the actual frequency region of 10 GHz.